1. Field of the Invention
The present invention is related to an authentication system of synchronizing instant timestamp and a method thereof.
2. Description of the Prior Art
Previously, for verifying the authenticity of a signature or a stamp on a paper document, or the paper document truly exists at a specific time, an unbiased third party unit is required, such as a notarization from the court or an attorney, to confirm the existence of the paper document and the authenticity of the signature or stamp.
Recently, regarding that more people or company using personal computer to produce electric documents, the demand of requesting a third party electrical authentication to authenticate the producing time and the content of digital information therefore increases as well.
As aforementioned, many third electric authentication institutes published corresponding techniques for electric authentication service. These electric authentication services are used to ensure the un-deniability of an electric document. For example, such as the technologies request the provider end of the electric document to stamp an electric stamp on the electric document or stamp a reliable digital timestamp on an electric document with digital signature. The digital timestamp is configured to combine a reliable date and time with the electric document, which is very common in electric business trade.
In the prior art of reference of China published application No. CN 103281292A, it disclosed several embodiments of digital timestamp applications:                1. Online bid to ensure accurate bidding sequence of priority;        2. Electric vote to ensure the voting is only validated within a promised time period;        3. Publishing to ensure the text is published within a given time period;        4. Online gambling to ensure the bet is made before the event; and        5. Digital copyright management to ensure a certain content is accessible when it is permitted.        
Among aforementioned applications, the common issue is that the consistency of machine time of an ideal digital timestamp. For an ideal digital timestamp mechanism, the accurate machine time is the most essential element in the verification. If the machine time of a digital timestamp of the electric document is simply provided by the provider end, since the machine time of a single machine is easily to be modified, the accuracy and the safety of the machine time is hard to be ensured. Besides, when the electric document or the electric trade process requires multiple digital timestamps from several parties, the difference or corrected difference of the machine time among these digital timestamps of these provider ends would be a potential problem seriously influencing the time verification accuracy of the digital timestamp.
To solve aforementioned problem of different machine times, some prior arts provide a plurality of solutions aiming on the machine time consistency issue. For example, the Network Time Protocol, NTP, is a protocol developed to provide a reliable time for single events. It allows different parties can evaluate the simultaneity of a event or time difference among different events. However, NTP is not capable of providing time approval and time indication.
The Wikipedia webpage of the title of “trusted timestamping” (http://en.wikipedia.org/wiki/Trusted_timestamping) describes several different solutions based on timestamp machine. But these solutions all rely on trusted authentication organizations or parties for providing timestamps.
In the one of the figures on that Wikipedia webpage, it describes that a provider end first proceeds an electric document by calculating hashes to generate a provider end hash information, and then sends the information to the trusted third party for electric authentication. The trusted third party adding a digital timestamp onto the provider end hash information and calculating the hashes again to generate the authentication end hash information. The authentication end hash information then is provided with a private key for encryption to generate an encrypted timestamp information. Then the encrypted timestamp information and the digital timestamp are transmitted back to the provider end simultaneously. The provider end then stores the electric document, the encrypted timestamp information, and digital timestamp together as a reliable timestamp electric document.
When a document receiver end retrieves the reliable timestamp electric document, and is demanded to prove the authenticity of the reliable timestamp electric document, it proceeds the electric document with the same hash calculating process done by the provider end to generate a receiver end hash information. The receiver end hash is then proceeded with the digital timestamp by calculating the same hash calculating process done by the trusted third party to generate a to-be-compared hash information. The encrypted timestamp information is decrypted by a public key to obtain the authentication end hash information. Then the to-be-compared hash information is compared with the authentication end hash information. If they are consistent, then the authentication passes, which means the reliable timestamp electric document received by the document receiver end is reliable, otherwise, the reliable timestamp electric document received by the document receiver end is not reliable.
As aforementioned description, the previous technologies of stamping digital timestamp on the electric document come with several disadvantages. It requires a reliable third party electric authentication providing reliable time and service of stamping authentication timestamp. And the third party electric authentication has to provide specific hash calculating procedure and verification service, such as Public Key Infrastructure technique, and these limitations make the technology more and more complex in stamping digital timestamp on the electric document. And, if the third party electric authentication fails in security, such as being attacked by hackers or backdoor programs, the security of authentication would be questioned as well, which would cause the whole authentication mechanism to lose its credibility and reliability.
Thus, to develop a simple, safer, and accurate system and method thereof for stamping digital timestamp on the electric document and verifying digital timestamp can be considered as an urgent issue.